Cholesterol oxidase

In enzymology, a cholesterol oxidase (EC 1.1.3.6) is an enzyme that catalyzes the chemical reaction

cholesterol + O2 cholest-4-en-3-one + H2O2
cholesterol oxidase
Identifiers
EC number1.1.3.6
CAS number9028-76-6
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
Cholesterol oxidase substrate-binding domain
crystal structure of cholesterol oxidase from b.sterolicum
Identifiers
SymbolChol_subst-bind
PfamPF09129
Pfam clanCL0277
InterProIPR015213
SCOP21i19 / SCOPe / SUPFAM

Thus, the two substrates of this enzyme are cholesterol and O2, whereas its two products are cholest-4-en-3-one and H2O2.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with oxygen as acceptor. The systematic name of this enzyme class is cholesterol:oxygen oxidoreductase. Other names in common use include cholesterol- O2 oxidoreductase, 3beta-hydroxy steroid oxidoreductase, and 3beta-hydroxysteroid:oxygen oxidoreductase. This enzyme participates in bile acid biosynthesis.

The substrate-binding domain found in some bacterial cholesterol oxidases is composed of an eight-stranded mixed beta-pleated sheet and six alpha-helices. This domain is positioned over the isoalloxazine ring system of the FAD cofactor bound by the FAD-binding domain and forms the roof of the active site cavity, allowing for catalysis of oxidation and isomerisation of cholesterol to cholest-4-en-3-one.[1]

Structural studies

As of late 2007, 14 structures have been solved for this class of enzymes, with PDB accession codes 1B4V, 1B8S, 1CBO, 1CC2, 1COY, 1I19, 1IJH, 1MXT, 1N1P, 1N4U, 1N4V, 1N4W, 2GEW, and 3COX.

References

  1. Coulombe R, Yue KQ, Ghisla S, Vrielink A (August 2001). "Oxygen access to the active site of cholesterol oxidase through a narrow channel is gated by an Arg-Glu pair". J. Biol. Chem. 276 (32): 30435–41. doi:10.1074/jbc.M104103200. PMID 11397813.

Further reading

  • Richmond W (1973). "Preparation and properties of a cholesterol oxidase from Nocardia sp. and its application to the enzymatic assay of total cholesterol in serum". Clin. Chem. 19 (12): 1350–6. doi:10.1093/clinchem/19.12.1350. PMID 4757363.
  • STADTMAN TC, CHERKES A, ANFINSEN CB (1954). "Studies on the microbiological degradation of cholesterol". J. Biol. Chem. 206 (2): 511–23. PMID 13143010.
This article incorporates text from the public domain Pfam and InterPro: IPR015213


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